Hydraulically driven compaction apparatus with improved electric control circuit



United States Patent CONTROL CIRCUIT v 11 Claims, snrawing Figs callylatched relay having a pair of COlIS energized through limit switchesWhlCl'l sense the extremes of the forward and U.S-

reverse movement of the blade one of the switches also 100/ 100/53controls the energization of a main relay for controlling the [51]Int.C| B30b 15/16 energization f th mp and the solenoids. The system isof Search 48, capable of everal modes of operation a ingle cycle 51, 52,53 of operation initiated manually or photoelectrically and terminatedautomatically, and continuous cycling initiated and [56] ReferencesC'ted terminated manually. A pressure-responsive switch deac- UNITEDSTATES PATENTS tivates the system when a compaction container is fullbut may 3,070,003 12/1962 Stacy 100/51 be overridden by jog switches topermit pinning of the load 3,229,618 1 1966 OConnor [OD/52X and precisepositioning of the blade.

Inventor Appl. No.

Filed Patented Assignee I-IYDRAULICALLY DRIVEN COMPACTION APPARATUSWlTI-I IMPROVED ELECTRIC Milton Clar 3,336,861 8/1967 Clar lOO/SOXBethesda, Maryland 3,368,478 2/1968 Clar 100/50 742,899 3,384,007 5/1968Boje et a1 l00/50X July 1968 Primary Examiner-Peter Feldman 1970Attorney-Shapiro and Shapiro Auto Pak Company H 1..

Bladensburg, Maryland a corporation oflhe District of Columbia ABSTRACT:Compaction apparatus for refuse and the like in which the compactionblade is driven forwardly and reversely by a hydraulic system includinga ram, an electric pump and a solenoid-actuated, center-neutral controlvalve. The solenoids of the control valve are energized alternately by amechani- SENSING KE YLOCK PRESS, SW.

REVlJOG so I72 Patented Oct. 20, 1970 Sheet 2 of2 SOL. B

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SOL. A

INVENTOR MILTON C LAR HYDRAULICALLY DRIVEN COMPACTION APPARATUS WITHIMPROVED ELECTRIC CONTROL CIRCUIT BACKGROUND OF THE INVENTION Thisinvention relates to compaction apparatus, and more particularly toimprovements in the electric control circuit employed in compactionapparatus, as for example, the apparatus disclosed and claimed in theapplicant's prior US. Pat. No. 3,368,478, granted Feb. 13, 1968, for"Compaction Apparatus".

The aforesaid Letters Patent discloses compaction apparatus in which thecompaction blade is driven forwardly and reversely by a hydraulic ramwhich forms part of a hydraulic system including a three-positioncontrol valve for directing hydraulic fluid to the ram so as to causethe ram to move forwardly or reversely. The electric control circuittherein disclosed employs separate forward and reverse relays forenergizing corresponding solenoids of the control valve in response tothe actuation of corresponding limit switches which sense the extremesof forward and reverse movement of the blade. Through the failure of arelay both solenoids of the valve can become energized concurrently. Itis desirable to avoid this condition and the resultant overload that cancause burnout of the solenoids.

The circuit disclosed in the said Letters Patent also provides forforward and reverse jogging of the blade and for deactivation of thecontrol system when the hydraulic pressure reaches a level indicative ofthe filling of the container into which the material is being compacted.In order to pin" the load in the container so that the container may beclosed it is sometimes necessary to exceed the pressure level whichwould normally deactivate the system, and it is desirable that thesystem remain active even though the pressure level is exceeded. It isalso desirable to provide other modes of operation in addition to themanually started and stopped operation of the said Letters Patent.

BRIEF DESCRIPTION OF THE INVENTION It is accordingly a principal objectof the present invention to provide improved compaction apparatus, andmore particularly a control system therefore which fulfills theforegoing needs.

Briefly stated, the preferred embodiment of the invention is concernedwith compaction apparatus of the type having a compaction blade drivenforwardly and reversely by a hydraulic system including a hydraulicmotor or ram, an electric pump, and a solenoid-actuated control valve. Amechanically latched relay is employed to energize the solenoids of thecontrol valve alternately, and the relay is actuated by a pair of limitswitches which sense the extremes of forward and reverse movement of theblade. One of the limit switches also controls the holding circuit of amain relay which extends electric power to the solenoids and to the pumpmotor starter relay. A pressure switch senses when the container intowhich material is compacted is full and actuates another mechanicallylatched relay for deactivating the system until a reset switch isoperated. Reverse and forward jog switches permit energization of thevalve solenoids selectively in order to pin the load and to position theblade precisely, and the pressure switch is overridden when the jogswitches are operated. In a manual operating mode the system operationis initiated manually and continues indefinitely until stopped manually(or by the pressure switch). In a first automatic mode operation isinitiated manually, proceeds through one cycle of reverse and forwardblade movement, and then terminates automatically. In a second automaticmode the same cycle is initiated in response to the sensing of materialto be compacted.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other objects,advantages, and features of the invention, and the manner in which thesame are accomplished will become more readily apparent uponconsideration of the following detailed description of the inventiontaken in conjunction with the accompanying drawings, which illustrate apreferred and exemplary embodiment, and wherein:

FIG. I is a schematic diagram of the electrical control circuit of theinvention;

FIG. 2 is a schematic diagram of the hydraulic circuit of typicalcompaction apparatus in which the invention may be incorporated; and

FIG. 3 is a side elevation view of typical compaction apparatus in whichthe invention may be incorporated.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings, FIG. 3illustrates compaction apparatus of the type disclosed in the aforesaidLetters Patent, to which reference is made for a complete description ofthe apparatus. The apparatus shown in FIG. 3 and described brieflyhereinafter is by way ofexample only, since it will be apparent to thoseskilled in the art that the invention may be employed in many other anddifferent types of compaction apparatus and the like. As shown, thecompaction apparatus may comprise a packer having a frame 10 with arectangular compaction chamber 12 at one end thereof surmounted by ahopper 14 into which material to be compacted may be placed foradmission to the compaction chamber through an inlet opening at the topthereof. The front 16 of the chamber has an outlet opening whichcommunicates with a corresponding opening in the rear of a suitablecontainer 18 detachably connected to the packer. A compaction blade 20reciprocates through the chamber 12, moving forwardly through an openingat the rear 22 of the compaction chamber and forcing material into thecontainer 18. The compaction blade is of boxlike configuration having avertical front wall 24 constituting the packing surface, a top wall 26,which blocks the inlet opening to the compaction chamber 12 when theblade is extended forwardly, a pair of L-shaped side walls 28, and ashort bottom wall 30. The rearward extensions of the side walls alongthe top wall 26 support blade guide means 32 which engage longitudinallyextending, tracks 34, and the bottom wall 30 similarly supports theblade upon the bottom wall of the compaction chamber. A verticallyadjustable deck 36 is provided to permit the user to move a receptacleto the hopper l4 and to empty the receptacle therein.

The compaction blade is driven forwardly and rearwardly by a hydraulicram 38, which in the exemplary form comprises a pair of hydrauliccylinders 40 and 42 fixed to each other side-by-side, one above theother, the cylinders containing pistons the rods 44 and 46 of whichextend in opposite directions and are fixed, respectively, to the backof the front wall 24 of the blade and a transverse frame member 48. Asdescribed in the said Letters Patent, when hydraulic fluid is suppliedto the ram 38 to extend the blade, both cylinders, which are supportedby their piston rods, move away from the frame member 48, and the blademoves away from the cylinders (to the right in FIG. 3). When the bladeis retracted, the movements are reversed.

FIG. 2 illustrates the hydraulic circuit, including a pump 50 driven byan electric motor 52 and a three-position control valve 54 actuated tofirst and second positions by solenoids A and B, respectively, andreturned to the illustrated centerneutral position by the usual springs56. In the neutral position the pump withdraws fluid from the reservoir58 and merely returns the fluid to the reservoir. When solenoid A isenergized, the valve 54 is shifted so that hydraulic fluid is directedto cylinders 40 and 42 to cause the blade to move rearwardly. Whensolenoid B is energized, valve 54 is shifted to reverse the fluid flowto the cylinders and cause the blade to move forwardly. A pressureswitch 60 responds to the hydraulic pressure from the pump 50 for apurpose to be described more fully hereinafter.

Referring to FIG. 1, wherein the solenoids A and B and the pump motor 52and pressure switch 60 just described are also shown, the electricalcontrol circuit of the invention may be supplied from a three-phasesource 62, the pump motor 52 being operated directly from thethree-phase supply and the remainder of the system operating upon singlephase AC by means of a transformer 64 the secondary winding 66 of whichhas one side connected to ground and the other side (the hot side)connected to a fuse 68, Motor 52 is energized upon energization of amotor starter relay CR3, the coil of which has one side connected toground by conductors 70, 72, 74 and switch section 76 of mechanicallylatched relay ML-l. The other side of the coil of relay CR3 is connectedby conductors 78 and 80, switch section 82 of a main relay CR1, andconductors 84 and 86 to the hot side of secondary winding 66. The coilof relay CR1 has one side connected by conductor 88 and one section 90of a keylock switch and by conductors 72 and 74 and switch 76 to ground.The other side of the coil of relay CR1 is connected by conductor 92 toone section of an automaticmanual switch and then by conductor 96 toswitch 98 of a photoelectric relay 100, the circuit continuing through asensing on-off switch section 102 and conductor 104 to the hot side ofsecondary winding 66. The said other side of the coil of relay CR1 isalso connected by conductor 106 to one section 108 of a cycle startswitch and then to the hot side of the secondary winding 66, and alsothrough section 110 of a reverse jog switch and by means of conductor112 through a similar section 114 of a forward jog switch to a stopswitch 116 and then by means of conductor 118 to the hot side ofsecondary winding 66.

When relay CR1 is energized, its switch section 120 closes and providesa holding circuit for the relay through conductor 122 and either (1)through conductor 124, section 126 of the automatic-manual switch,section 128 of the reverse jog switch, conductor 130, section 132 of theforward jog switch, stop switch 116, and conductor 118 to the hot sideof secondary winding 66 or (2) through the upper contact of a limitswitch LS1 and conductor 134 and then through switch section 128, etc.as before. Energization of relay CR1 also extends a circuit from the hotside of secondary winding 66, conductors 86 and 84, and closed switchsection 82 to conductor 80 and then through conductor 136 to switchsections 138 and 140 of a two-position mechanically latching relay ML-2.Switch sections 138 and 140 are closed alternately upon energization ofcoils 142 and 144, respectively, the moving switch contacts beingmechanically latched to close one switch section after energization ofthe corresponding coil, until the energization of the other coil,whereupon the alternate switch section is closed and mechanicallylatched. Switch sections 138 and 140 extend energization circuits tosolenoids A and B which are connected to ground through a switch 146,conductor 148, conductor 74 and switch section 76. Coils 142 and 144 areenergized when the corresponding limit switches LS1 and LS2 are closedupon their lower contacts so as to extend energization circuits fromconductor 134.

Coil 142 may also be energized through a circuit including conductor150, section 152 of the automatic-manual switch, conductor 154, section156 of the sensing on-off switch and section 158 of the cycle startswitch to the hot side of the secondary winding 66. A furtherenergization circuit for coil 142 is provided by conductor 160, section162 of the reverse jog switch, stop switch 116, and conductor 1 18 tothe hot side of secondary winding 66. Coil 144 may be energized by acircuit including conductor 164, section 166 of the forward jog switch,stop switch 116 and conductor 118 to the hot side of the secondarywinding 66.

Relay ML-l is a mechanically latching relay, which, like relay ML-Z,includes a pair of coils 168 and 170 for closing the switch sections 76and 172 alternately. Coil 168 is energized by a circuit which extendsfrom ground, through the coil, conductor 174, section 176 of the forwardjog switch, section 178 of the reverse jog switch, conductor 180, thepreviously described pressure switch 60, and conductor 86 to the hotside of secondary winding 66. Coil 170 may be energized by a circuitextending from ground, through the coil, through a normally open resetswitch 182, conductor 184, and conductor 86 to the hot side of secondarywinding 66. When switch section 172 is closed, an indicator lamp 186 islit. Similarly, when the keylock switch is closed, switch section 188completes an energization circuit for an indicator lamp 190. Thephotoelectric relay has its own source of illumination, lamp 192, whichis energized when section 102 of the sensing on-off switch is closed.

The operation of the circuit of FIG. 1 is as follows:

To prepare the system for operation, the keylock switch, includingsections 90 and 188, is closed, and lamp 190 lights to indicate that thesystem is operative. it is assumed that the sensing on-off switch is inthe off position as illustrated, that is, with switch section 156closed, and that the automatic manual switch is in the manual' positionas illustrated, that is, with switch sections 94 and 152 open and switchsection 126 closed. To start a manual cycle, the normally open cyclestart switch is actuated momentarily, so as to close switch sections 108and 158. The momentary closing of switch 108 completes a circuit throughconductor 106 for energizing the coil of relay CR1, and this relaycloses its contacts. The closing of switch of the relay completes aholding circuit for the relay through conductor 122, conductor 124,switch section 126, switch section 128, conductor 130, switch section132, switch 116, conductor 118, to the hot side of the secondary winding66. Relay CR1 thus remains energized when the cycle start switch isreleased. The closing of switch 82 of the relay extends an energizationcircuit from the hot side of the secondary winding 66 through conductors84, 80 and 78 to the coil of relay CR3, which closes its contacts andenergizes pump motor 52. Hydraulic fluid is now supplied to the controlvalve 54(F1G. 2).

The closing of switch 82 also extends an energization circuit throughconductors 80 and 136 and through whichever of switch sections 138 andis closed to solenoid A or solenoid B. One of the solenoids will thus beenergized and will move the control valve 54 so as to cause thecompaction blade to move in the direction in which it was moving whenthe circuit was last energized. Assuming that switch section 138 isclosed, as shown, solenoid A will be energized, and the blade will moverearwardly until an actuator cam (not shown) supported at the rear ofthe blade engages the actuating arm of limit switch LS2, which ispositioned at the rear of the compactor frame as indicated in FIG. 3.When switch LS2 closes, coil 144 is energized, opening switch section138 and closing switch section 140. Solenoid A is thus deenergized andsolenoid B energized, so that the control valve 54 moves to reverse theflow of hydraulic fluid to the driving ram and thus to cause the bladeto move forwardly. The blade moves forwardly until the actuating camengages the actuating arm of limit switch LS1, which may be supportedadjacent to the rear of the compaction chamber 12 as shown in FIG. 3,closing switch LS1 upon its lower contact and energizing coil 142.Switch section 140 will thus be opened and switch section 138 closed,deenergizing solenoid B and energizing solenoid A again so as to reversethe movement of the blade and cause the blade to move rearwardly again.The blade will continue to cycle in this manner until the stop switch116 is actuated, which will break the holding circuit for relay CR1described previously. The blade will stop in whatever position it islocated when the stop switch 116 is actuated. When the cycle startswitch isagain actuated, the blade will commence moving again in thesame direction it was moving when it was stopped.

For automatic operation the automatic-manual switch is shifted to closeswitch section 94, open switch section 126 and close switch section 152.When the cycle start switch is again actuated momentarily, relay CR1will again be energized through switch section 108 and conductor 106 andwill close its contacts. Limit switch LS1 will be closed upon its uppercontact (assuming that the blade is not in its extreme forward position)and will complete a holding circuit for relay CR1 as describedpreviously. Energization of relay CR1 will cause energization of motorstarter relay CR3 as before. The momentary closing of switch section 158of the cycle start switch will complete a circuit through switch section156, conductor 4, switch section 152, and conductor 150 to coil 142 ofrelay ML-Z. Switch section 138 will thus be closed, energizing solenoidA and causing the blade to move rearwardly. in automatic operation theblade always commences its movement by moving rearwardly, unless theblade is already at its extreme rearward position The blade willcontinue to move rearwardly until limit switch LS2 is closed, and thenrelay coil 144 will be energized and the blade movement reversed asdescribed in connection with the manual mode of operation. The bladewill now move forwardly until limit switch LS1 is actuated, whereuponthe limit switch will transfer from its upper contact to its lowercontact, breaking the holding circuit for relay CR1 and deenergizing themotor starter relay CR3. The blade will now come to rest.

For automatic operation initiated in response to the presence ofmaterial to be compacted, the sensing on-off switch is moved to closeswitch section 102 and open switch section 156, thereby energizing thelamp 192 and the photoelectric relay 100. The lamp 192 may be located atthe inlet opening of the compaction chamber slightly above the blade, asindicated in FIG. 3, with the photoelectric cell located at the oppositeside of the compaction chamber, suitable openings in the side walls ofthe chamber being provided to permit a light beam to pass from lamp 192to the photocell. A more detailed description of such a sensing schememay be found in the applicant's prior US. Pat. No. 3,231 ,107, grantedJan. 25, 1966, for Apparatus for the Compaction and Disposal of Refuse.Switch 98 of the relay will normally be open. If, however, the lightbeam is interrupted by material placed in the hopper 14, switch 98 willclose, completing a circuit from the hot side of secondary winding 66through conductor 104, switch section 102, switch 98, conductor 96,switch section 94, and conductor 92 to relay CR1. The apparatus willthen operate as above stated for manually initiated automatic operation,the light beam being reestablished and switch 98 opening when the blademoves rearwardly sufficiently to permit the material on top of the bladeto drop into the compaction chamber.

if during the course of operation the container becomes filled or aserious obstruction is encountered, the hydraulic pressure supplied bythe pump will rise sufficiently to actuate the pressure switch 60, whichis set to operate at a predetermined high pressure level, and coil 168of relay ML-1 will be energized, opening switch section 76 and closingswitch section 172. The opening of switch section 76 will deenergizerelays CR1 and CR3, and the blade will come to a halt. The closing ofswitch section 172 will light lamp 186 to indicate that the container isfull or that attention of the operator is required. To reinstituteoperation the operator momentarily closes reset switch 182 in order toenergize coil 170 and return the mechanically latched relay to thecondition illustrated in FIG. 1.

The forward and reverse jog switches permit precise positioning of theblade and permit the blade to be moved forward sufficiently to pin theload in the container, so that the container may be closed. it will benoted that when the jog switches are actuated, the circuit to thepressure switch is broken, so that the pressure switch does notinterfere with the pinning operation even though the actuating level ofthe pressure switch is exceeded temporarily. Switch section 162 of thereverse jog switch is connected to relay coil 142 and switch section 166of the forward jog switch is connected to relay coil 144, so thatsolenoids A and B may be energized selectively. Switch sections 128 and132 are opened when the jog switches are actuated, so as to disable thecircuits through the limit switches LS1 and LS2 and render the limitswitches ineffective.

Switch 146 is provided to permit warmup" of the hydraulic fluid in coldweather. If this switch is opened, the cycle start switch may beactuated to energize pump while energization of the solenoids isprevented. The control valve will thus remain in its neutral positionuntil switch 146 is closed.

While a preferred embodiment of the invention has been shown anddescribed, it will be apparent to those skilled in the art that changescan be made in this embodiment without departing from the principles andspirit of the invention, the scope of which is defined in the appendedclaims. For example, if conductor 122 is connected to an upper contactof LS2, rather than to LS1, the compaction blade can be made to stopautomatically in its fully retracted position and to move forwardly tostart an automatic cycle.

I claim:

1. in compaction apparatus and the like having a compaction blade drivenforwardly and rearwardly by a hydraulic ram, valve means for controllingthe supply of hydraulic fluid to said ram and for determining thedirection of movement of said blade, a single relay means having a pairof separately energizable means for moving a common switch tocorresponding positions in order to control the operation of said valvemeans for forward or rearward movement of said blade depending uponwhich of said energizable means is energized, a pair of limit switchescorresponding. respectively. to the extremes of forward and rearwardmovement of said blade, the forward limit switch having a first positionfor permitting completion of an energization circuit for one of saidenergizable means, the rearward limit switch having a first position forpermitting completion of an energization circuit for the otherenergizable means, said blade having means for moving said forward limitswitch to said first position when said blade reaches said forwardextreme and having means for moving said rearward limit switch to itsfirst position when said blade reaches said rearward extreme, wherebysaid energizable means are energized alternately for controlling saidvalve means and for causing said blade to move between said rearward andforward extremes.

2. The apparatus of claim 1, said valve means having a pair ofelectrical actuating means for positioning the valve means to cause saidblade to move forwardly or rearwardly, respectively, said switch of saidrelay means comprising means for energizing said actuating meansalternately.

3. The apparatus of claim 2, said relay means comprising a pair ofactuating coils connected to said limit switches, respectively, andhaving means for latching its switch in whichever position it is movedby one of said coils until the other coil is energized.

4. The apparatus of claim 2, further comprising additional relay meansfor controlling a circuit through the switch of the first-mentionedrelay means to said valve actuating means, one of said limit switcheshaving an alternate position for controlling the energization of saidadditional relay means.

5. The apparatus of claim 4, further comprising an electric pump forsupplying hydraulic fluid to said valve means, said additional relaymeans having means for controlling the energization of said pump.

6. in compaction apparatus and the like having a compaction blade drivenby a hydraulic ram, valve means for controlling the flow of hydraulicfluid to said ram for causing said ram to move forwardly or rearwardlyin accordance with the position of said valve means and having a pair ofsolenoids for moving said valve means to its forward and rearwardpositions, respectively, and a single forward and rearward relay meansincluding a mechanically latched switch for energizing said solenoidsalternately.

7. The apparatus of claim 6, further comprising switch means responsiveto forward and rearward movement of said blade, respectively, foractuating said relay means to place said mechanically latched switch inone position or the other.

8. The apparatus of claim 6, said relay means having forward andrearward actuating coils, said apparatus further comprising a pair oflimit switches for energizing the forward and rearward relay coils whenthe blade reaches corresponding rearward and forward positions,respectively, and further comprising reverse jog switch means andforward jog switch means for energizing said rearward coil and saidforward coil, respectively, and for preventing said limit switches fromenergizing said coils.

9. ln compaction apparatus and the like of the type having a 11. Incompaction apparatus and the like of the type having compaction bladedriven by a hydraulic system including cona compaction blade drivenforwardly and rearwardly by a "Oi VQiVC means fOl' determining WhCIhCl'said blade 15 (.iliVCl'l hydraulic system including an electric pump andcontrol valve fol'wardly or rearwardly- Pressure switch means responsivcto means for determining whether said blade is driven forwardly thehydraulic P in Said System for deactivating Said or rcarwardly, a pairof limit switches each having a first posi- F when a predmcmlincdPressure level is reached Jbg tion to which the switch is moved when theblade reaches an Sw'tch means for actummg and control valve meansextreme of its forward and rearward movement, respectively meansresponsive to operation of said jog switch means for for actuatin 1 saidcontrol valve means to r w rs I he rendering said pressure switch meansincapable ot deactivat- L L x t dlrum n ol movement of said blade andone of said switches having an ing said system. It)

The apparatus Ofcluim 9 Said system having a mcchzm-b alternate positiontor controlling the energization ot said cally latched relay normallyresponsive to said pressure switch pump means for deactivating saidsystem.

